As is known, a significant contribution directed to the desulfurization of coal and ores is described and claimed in the Arthur E. Starbuck U.S. Re. Pat. No. 32,454, data Jul. 7, 1987, and entitled PROCESS FOR DESULFURIZATION OF COALS AND ORES, owned of record, by means assignment, by Midwest Ore Processing Company, Inc., the same assignee as the invention presented herein. The teachings of the aforesaid patent are incorporated by reference herein.
Importance of the aforesaid Starbuck process lies in the usage of the solvent perchloroethylene to form a liquor in which sulfur dissolves in the solution. The patentee states that the desulfurization process is effective to the extent that less than 0.01 percent free sulfur remains in the coal product after drying. The invention involves pretreatment of the coal under process for even greater organic sulfur removal than achievable heretofore.